Frequently the cost of concrete forms and the time required to assemble the forms greatly exceeds the cost of the concrete itself and the pouring of the wall configuration. The forms are quite bulky, are difficult to handle, and require a large number of man hours to assemble and dissemble.
As a solution to this problem, I developed a concrete form apparatus as disclosed in U.S. Pat. No. 3,548,467. The apparatus disclosed functioned to support portable forms as an elongated concrete wall is being poured. Concrete was poured between two forms using movable supporting tracks and a series of carriages that moved vertically oriented backup rollers along outwardly facing surfaces of the forms. The rollers prevented the forms from buckling or bulging as concrete was progressively poured. This apparatus included an independent motor for each of the upright rollers on each carriage. Operation of the motors would cause rotation of the rollers and corresponding movement of the roller pair along the forms.
Difficulty was experienced, however, with the independently operating motors. In practice, hydraulic motors were utilized. It was found that slight pressure variations in the hydraulic lines would cause the motors to operate at slightly varying speeds. This would have the effect of slowing or speeding one of the rollers in relation to the other.
The rollers, being tied together by carriages at the upward ends thereof, could therefore become undesirably angularly oriented relative to the wall. The rollers would thus being against the sheet forms.
Another problem encountered with the dual motor arrangement was observed at corners.
The drive motor and roller at the inside of the wall was required to slow or come to a complete stop while the roller and motor at the outside of the wall were operated to move around the outside corner. Difficulty was experienced in properly controlling this function utilizing the two individual motors.
The present invention was conceived to overcome the above problems while maintaining the desirable features of the concrete wall forming apparatus shown in my issued U.S. Pat. No. 3,548,467.